One of the things that distinguishes a real player economy from a simulated one is emergent supply chains. In most single-player games, the economy is a facade — you sell things to vendors at fixed prices, buy things from vendors at fixed prices, and no market dynamic emerges because there is no other party. In IdleWorlds, a supply chain formed in the first weeks of the market being open, and nobody explicitly designed it. It materialized because the systems connect in ways that create mutual dependency.
The base chain is simple: a miner produces ore they don't personally need to smelt, because they are idling a zone that's below their current tier. That ore is listed. A smith who focuses on production rather than combat needs ore steadily and doesn't want to interrupt their crafting loop to go mine. They buy from the miner. The smith produces gear beyond what they personally equip — swords, shields, armor — and lists the excess. A combat-focused player whose smithing skill hasn't kept up with their zone needs gear to push the next zone's recommended stats. They buy from the smith. That player's combat sessions produce gold, which circulates back into the market. Herbalists who specialize in potion production sell XP buffs to the fighters who need them to level faster.
Nobody coordinated any of this. The miner didn't know they were supplying a production smith. The smith didn't know who would buy the armor. The supply chain formed because each participant was solving their own bottleneck and the market created a mechanism for those individual solutions to find each other. That is what a healthy player economy looks like at its most basic.
The more interesting question is what happens as the game's population grows and more zones open. Supply chains become tiered. Zone 1 ore is abundant and cheap. Zone 6 ore is scarcer, produced by fewer players, and commands a premium. High-tier potions are limited by how many herbalists have reached that zone's herb and how efficiently they are running their alchemy loops. The market price of any item is implicitly a signal about the supply depth at that tier, which is in turn a signal about how many active players are working that zone.
Specialization is where this gets strategically deep. A player who decides to focus primarily on herbing and alchemy — running at a zone tier for the herb, producing potions, listing aggressively — can often generate more gold per hour than a player running combat at the same zone, because the demand for XP buffs is both persistent and inelastic. Players who understand this will carve out economic niches. Over time, the market starts to have identifiable specialists rather than everyone doing everything.
The gem economy introduced by Jewelcrafting adds another layer. Gems from different zone tiers will have wildly different supply rates based on how many active players are prospecting at each tier. The demand side — gem crafting recipes — doesn't exist yet, which means when it ships, the market will have to price discovery across 34 distinct gem types simultaneously. That is a genuinely interesting economic event, and it will play out entirely through player behavior in the market. No developer intervention required.